Cable-type secondary battery

ABSTRACT

A cable-type secondary battery, includes an electrode assembly including first and second polarity electrodes with a thin and long shape, each electrode having a current collector whose cross-section perpendicular to its longitudinal direction is a circular, asymmetrical oval or polygonal shape, and an electrode active material applied onto the surface of the current collector, and a separator or an electrolyte layer interposed between the first and second polarity electrodes; and a cover member surrounding the electrode assembly. Also, the cable-type secondary battery is provided with a first polarity terminal and a second polarity terminal connected to the first polarity electrode and the second polarity electrode, respectively, at the end of the cable-type secondary battery; and a housing cap configured to fix the first and second polarity terminals and cover the end of the cable-type secondary battery.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of International ApplicationNo. PCT/KR2012/006557 filed Aug. 17, 2012, which claims priority toKorean Patent Application No. 10-2011-0082992 filed in the Republic ofKorea on Aug. 19, 2011 and Korean Patent Application No. 10-2012-0089275filed in the Republic of Korea on Aug. 16, 2012, the disclosures ofwhich are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a cable-type secondary battery, andmore particularly, to a terminal of the cable-type secondary battery.

BACKGROUND ART

Recently, advances in wireless communication technologies have led tothe popularization of mobile devices, and to keep pace with this trend,there is a strong tendency to use secondary batteries as a power sourceof mobile devices. Secondary batteries are also used as a power sourceof environmentally friendly next-generation vehicles such as electricvehicles and hybrid vehicles.

As described above, as the use of secondary batteries is dramaticallyincreasing in many fields of industry, secondary batteries are varyingin output, capacity, structure, and the like, depending on thecharacteristics of the field where the secondary batteries are used.

Generally, a secondary battery is provided with an electrode assemblyincluding a cathode and an anode, each having a plate-like currentcollector surface-coated with an active material, and a separatorinterposed between the cathode and the anode. The electrode assembly isreceived in a cylindrical or prismatic metal casing or a pouch-typecasing of an aluminum laminate sheet, together with a liquid electrolyteor a solid electrolyte. To improve the capacity of the secondarybattery, the electrode assembly may be a jelly-roll type in which acathode sheet, a separator sheet, and an anode sheet are rolledtogether, or a stack-type in which a plurality of unit electrodes of athin plate shape are sequentially stacked. Accordingly, the electrode(cathode and anode) of the electrode assembly has a substantiallyplate-like structure.

The conventional plate-like electrode structure is advantageous in thatit has a high degree of integration when rolling or stacking, but hasdifficulty in adaptively changing the structure to meet the demand ofthe industrial field. Furthermore, the plate-like electrode structurehas various problems in that it is sensitive to the change in volume ofthe electrode during charging or discharging, the gas generated in thecell may not easily discharge, and the potential difference between theelectrodes may increase.

Particularly, to meet the various needs of the users, the kinds ofdevices using secondary batteries are diversifying and a lot of emphasisis put on designing such devices. However, devices having a specialshape need to offer a separate portion or space for mounting secondarybatteries having a traditional structure and/or shape (cylindrical,prismatic, or pouch-type), which becomes a great obstacle to theexpansion of wireless technologies and when developing new designs. Forexample, when a newly developed device has an elongated space formounting a secondary battery, it is substantially impossible or veryinefficient to structurally change the secondary battery including anelectrode assembly made up of existing plate-like electrodes to suit thestructure to the mounting space. In other words, since the conventionalcylindrical, coin-type, and prismatic batteries have specific shapes,the batteries are limited in its use and ability to freely deform.Accordingly, it is difficult to adaptively deform, for example, twist orbend, the batteries depending on its use.

To solve these problems, the inventors of the present invention havedisclosed Korean Patent No. 10-0804411 (filed on Jan. 17, 2006 andregistered on Feb. 12, 2008) entitled “Electrode Assembly of NovelStructure and Secondary Battery Comprising the Same”, all the contentsof which are incorporated herein by reference.

This type of secondary battery (hereinafter, referred to as a cable-typesecondary battery) is configured in a thin and long shape and have acable structure capable of being flexible in a longitudinal direction.However, when such a cable-type secondary battery having a relativelylong linear shape and excellent flexibility is used in a device, thecable-type secondary battery may be excessively deformed by theapplication of an external force and this causes the weakness of thecoupling between the device and the cable-type secondary battery.Therefore, in the case of the cable-type secondary battery, unlike theexisting battery terminal, a battery terminal capable of stronglycoupling to the device may be required. Accordingly, there is anincreasing need for developing a cable-type secondary battery having aterminal.

DISCLOSURE Technical Problem

The present invention is designed to solve the problems of the priorart, and therefore it is an object of the present invention to provide acable-type secondary battery including a battery terminal at one endthereof.

Technical Solution

The present invention is designed in consideration of the problems ofthe prior art, and therefore it is an object of the present invention toprovide a cable-type secondary battery, comprising an electrode assemblyincluding first and second polarity electrodes with a thin and longshape, each electrode having a current collector whose cross-sectionperpendicular to its longitudinal direction is a circular, asymmetricaloval or polygonal shape and an electrode active material applied ontothe surface of the current collector, and a separator or an electrolytelayer interposed between the first and second polarity electrodes; and acover member surrounding the electrode assembly, wherein the cable-typesecondary battery is provided with a first polarity terminal and asecond polarity terminal connected to the first polarity electrode andthe second polarity electrode, respectively, at the end of thecable-type secondary battery; and a housing cap configured to fix thefirst and second polarity terminals and cover the end of the cable-typesecondary battery.

Preferably, the housing cap includes a coupling unit at the outsidethereof. Such a coupling unit may include a spiral groove or a spiralprotrusion for screw-coupling.

Also, the coupling unit may include a groove or protrusion forinsertion-coupling.

Further, the second polarity terminal may be integrated with the housingcap.

Furthermore, the first polarity electrode may be a cathode and thesecond polarity electrode may be an anode; or the first polarityelectrode may be an anode and the second polarity electrode may be acathode.

Further, it is another object of the present invention to provide adevice, comprising a power mounting unit capable of mounting acable-type secondary battery as a power source, wherein the powermounting unit includes a protruded-type coupling unit or anindented-type coupling unit configured to correspond to the couplingunit of the cable-type secondary battery.

ADVANTAGEOUS EFFECTS

According to the present invention, since all electrode terminals of acable-type secondary battery are disposed at one end thereof, thecable-type secondary battery can be easily connected to a device. Also,since a cable-type secondary battery is provided with a coupling unit,the cable-type secondary battery can be strongly coupled to a device.

DESCRIPTION OF DRAWINGS

The accompanying drawings illustrate preferred embodiments of thepresent disclosure and, together with the following detaileddescription, serve to provide further understanding of the technicalspirit of the present disclosure. However, the present invention is notto be construed as being limited to the drawings:

FIG. 1 is a perspective view schematically showing a cable-typesecondary battery according to a preferred embodiment of the presentinvention, which is provided with a housing cap including a spiralprotrusion for screw-coupling as a coupling unit;

FIG. 2 is a cross-sectional view of FIG. 1;

FIG. 3 is an extracted perspective view showing the main portion of aone end of a cable-type secondary battery according to a preferredembodiment of the present invention;

FIG. 4 is a cross-sectional view of FIG. 3;

FIG. 5 is a perspective view schematically showing a cable-typesecondary battery according to a preferred embodiment of the presentinvention, which is provided with a housing cap including a protrusionfor insertion-coupling as a coupling unit;

FIG. 6 is a cross-sectional view of FIG. 5;

FIG. 7 is a perspective view schematically showing a cable-typesecondary battery in a sheet shape according to a preferred embodimentof the present invention, which is provided with a housing cap includinga protrusion for insertion-coupling as a coupling unit;

FIG. 8 is a cross-sectional view of FIG. 7; and

FIG. 9 is an extracted perspective view showing a cable-type secondarybattery in the form of a sheet, according to a preferred embodiment ofthe present invention.

<Explanation of Reference Numerals> 10: Cable-type secondary battery10′: Secondary battery having a plurality of cable-type secondarybatteries are connected to each other 20, 30, 40: Cable-type secondarybattery having a polarity terminal 1: First polarity current collector2: Anode active material 3: Separator 4: Cathode active material 5:Second polarity current collector 6: Protection coating 11: Firstpolarity electrode 12: Second polarity electrode 21, 31, 41: Firstpolarity terminal 22, 32, 42: Second polarity terminal 25, 35, 45:Housing cap 26, 36, 46: Coupling unit

BEST MODE

Hereinafter, the present invention will be described in detail withreference to the accompanying drawings. Prior to the description, itshould be understood that the terms used in the specification and theappended claims should not be construed as limited to general anddictionary meanings, but interpreted based on the meanings and conceptscorresponding to technical aspects of the present invention on the basisof the principle that the inventor is allowed to define termsappropriately for the best explanation.

Preferred embodiments of the present invention will be explained withreference to the accompanying drawings.

FIG. 1 is a perspective view schematically showing a cable-typesecondary battery according to a preferred embodiment of the presentinvention, which is provided with a housing cap including a spiralprotrusion for screw-coupling as a coupling unit, and FIG. 2 is across-sectional view of FIG. 1.

Referring to FIGS. 1 and 2, the cable-type secondary battery 20according to a preferred embodiment of the present invention includesfirst and second polarity terminals 21, 22 respectively coupled to firstand second polarity electrodes 11, 12 at one end portion of thecable-type secondary battery; and a housing cap 25 configured to fix thefirst and second polarity terminals 21, 22 and to cover theabove-mentioned end portion. The electrodes may be respectivelyconnected to the terminal 21, 22 by the transformation thereof or usingan additional connecting line. Through these terminals 21, 22, electricenergy may be supplied to charge the cable-type secondary battery.

According to the embodiment as described above, each cable-typesecondary battery 10 is provided with a thin and long shaped electrodeassembly including a first polarity electrode, a second polarityelectrode, and a separator interposed between the first polarityelectrode and the second polarity electrode. Each of the first andsecond polarity electrodes is configured by applying an electrode activematerial onto the surface of a current collector whose cross sectionperpendicular to the longitudinal direction is a circular, oval (e.g.,symmetric oval or asymmetric oval) or polygonal shape. The firstpolarity electrode is either a cathode or an anode, and the secondpolarity electrode is either an anode or a cathode corresponding to thefirst polarity electrode. Such an electrode assembly is described inKorean Patent No. 10-0804411 (filed Jan. 17, 2006 and registered on Feb.12, 2008) entitled “Electrode Assembly of Novel Structure and SecondaryBattery Comprising the Same”, all the contents of which are incorporatedherein by reference.

FIG. 3 is an extracted perspective view showing main portions of acable-type secondary battery according to a preferred embodiment of thepresent invention, and FIG. 4 is a cross-sectional view of FIG. 3. Thesame reference numerals are regarded as indicating the elements havingthe same function as those of FIGS. 1 and 2.

Referring to FIGS. 3 and 4, a single strip-shaped cable-type secondarybattery 10 according to a preferred embodiment of the present inventionis configured with an electrode assembly, unlike the conventionalplate-like electrode assembly in which an electrode active material isdispersed onto the two-dimensional current collector surface, such as ametal foil, and a protection coating 6 covering the outer surface of theelectrode assembly. The electrode assembly includes a first polaritycurrent collector 1, a three-dimensional anode current collector shapedas a thin and long wire and having a circle-shaped cross-section; ananode active material 2 provided on the surface of the first polaritycurrent collector 1; a separating element 3 having a separator or anelectrolyte and provided on the outer surface of the anode activematerial 2; a cathode active material 4 formed on the outer surface ofthe separating element 3; and a second polarity current collector 5(i.e., a cathode current collector) provided on the outer surface of thecathode active material 4. Here, the order of the cathode and the anodemay be conversed. That is, it will be understood by a person havingordinary skill in the art that the cable-type secondary battery may beconfigured by forming a cathode current collector having a thin and longwire shape in the center of the electrode assembly, and then forming thecathode active material, the separating element, the anode activematerial, and the anode current collector in order from the outside ofthe cathode current collector.

Meanwhile, the circle-shaped cross-section of the current collector mayinclude a complete symmetrical circle structure and an oval structure(e.g., a symmetrical oval or an asymmetrical oval). A current collector,with the exception of a two dimensional plate shape, may have apolygonal-shaped cross-section including a triangular structure, aquadrangular structure, a pentagonal structure, a hexagonal structure,or the like and the corners of these structures may be in an angularshape or a circular shape, but is not particularly limited thereto.Also, the electrode active material is dispersed on the surface of thecurrent collector having a circle-shaped structure or a polygonal-shapedstructure, and acts to move electrons through the current collector bythe intercalation/deintercalation of ions into and from an electrolyte,similar to that of the conventional secondary battery.

According to an alternative embodiment of the present invention, amulti-strip shaped cable-type secondary battery may be configured byforming an electrolyte layer in a cylindrical form around an anodebundle consisting of a plurality of anode units, in which an anodeactive material is applied on the anode current collector having a thinand long shape; providing a cathode active material on the outer surfaceof the electrolyte layer; forming a cathode current collector on theouter surface of the cathode active material; and providing a protectioncoating on the outer surface of the cathode current collector. Also,according to another modified embodiment of the present invention, amulti strip-shaped cable-type secondary battery may also be configuredby forming a bundle of assemblies, in which an electrolyte layer isformed on the outer surface of an anode unit; forming a cathode activematerial layer in a cylindrical form around the bundle; forming acathode current collector on the outer surface of the cathode activematerial layer; and forming a protection coating on the outer surface ofthe cathode current collector. According to still another modifiedembodiment of the present invention, a multi strip-shaped cable-typesecondary battery may also be configured by forming bundles of aplurality of anode units and cathode units, in which each correspondingactive material is applied on the outer surface of each wire-shapedcurrent collector, the outer of either the anode units or the cathodeunits being surrounded by a first electrolyte layer; forming a secondelectrolyte layer in a cylindrical form around the bundle; andsurrounding the second electrolyte layer with a protection coating.

Generally, when such a cable-type secondary battery having a relativelylong linear shape and excellent flexibility is used in a device, thecable-type secondary battery may be excessively deformed by theapplication of an external force and this causes the weakness of thecoupling between the device and the cable-type secondary. Therefore, inthe case of the cable-type secondary battery, unlike the existingbattery terminal, a battery terminal capable of strongly coupling to thedevice may be required. To achieve this, the housing cap 25 of thepresent invention is preferably formed to have a coupling unit 26 on theouter surface of the housing cap 25.

The coupling unit 26 may have a spiral-shaped groove or a spiralprotrusion for screw-coupling. The screw-coupling is carried out byrotating a female screw and a male screw having a spiral groove and aspiral protrusion, respectively, for coupling. According to this method,force is dispersed at the coupling portion to achieve strong coupling.

Also, the second polarity terminal 22 may be integrated with the housingcap 25. In this case, by configuring a part of the housing cap 25 as aconductor and connecting the conductor to an electrode, the housing cap25 may act as a polarity terminal.

FIG. 5 is a perspective view schematically showing a cable-typesecondary battery according to a preferred embodiment of the presentinvention, which is provided with a housing cap including a protrusionfor insertion coupling as a coupling unit, and FIG. 6 is across-sectional view of FIG. 5.

Referring to FIGS. 5 and 6, according to another preferred embodiment ofthe present invention, the cable-type secondary battery 30 of thepresent invention may have the housing cap 35 in which a coupling unit36, such as a groove or protrusion, is formed for insertion-coupling.The insertion-coupling is carried out by applying external force whencoupling is made to hold a groove or protrusion by a fixing member. Sucha fixing member may be pushed by a spring or the like to fix the grooveor protrusion at the correct position thereof and may be configured witha hook structure capable of being decoupled by a user's pressure. Also,it will be obvious to those skilled in the art that the fixing membermay include not only the above-mentioned hook structure, but alsovarious elements required for any type of fixing which has beenwell-known or will be known in the future, such as latches, fasteners,fixing plates, fixing buttons, rotatable screws, radial ring, or thelike.

Also, the first polarity terminal 31 and the second polarity terminal 32may be individually formed and be fixed by using the housing cap 35.

FIG. 7 is a perspective view schematically showing a cable-typesecondary battery in the form of a sheet, according to a preferredembodiment of the present invention which is provided with a housing capincluding a protrusion for insertion-coupling as a coupling unit, andFIG. 8 is a cross-sectional view of FIG. 7.

Referring to FIGS. 7 and 8, the cable-type secondary battery accordingto another preferred embodiment of the present invention may be acable-type secondary battery shaped as a sheet and including the housingcap 45 in which a protrusion 46 for insertion-coupling of a cable-typesecondary battery 40 is formed as a coupling unit.

According to an alternative embodiment of the present invention, thecable-type secondary battery 40 in a sheet shape may be configured witha secondary battery 10′ in which a plurality of cable-type secondarybatteries are connected to each other as shown in FIG. 9 or with asingle cable-type secondary battery, the cross-section of which istransformed to have a sheet shape. When the cable-type secondary battery10′ in which a plurality of cable-type secondary batteries are connectedto each other is used, a plurality of electrodes included in thecable-type secondary battery are connected, and then, the connectedelectrodes are connected to a first polarity terminal 41 and a secondpolarity terminal 42.

In addition, the present invention provides a device which allows thecable-type secondary battery to be connected thereto as a power source,when necessary, and has a mounting unit for mounting the cable-typesecondary battery. The mounting unit includes a coupling unit, such as aprotruded-type coupling unit or an indented-type coupling unit, whichcorresponds to the coupling unit of the cable-type secondary battery.

Meanwhile, it should be understood that the above description and theaccompanying drawings represent a preferred embodiment of the presentinvention and various changes and modifications, combinations and/orsubstitutions of the embodiments described herein can be made withoutdeparting from the scope and spirit of the invention as defined by theappended claims. Particularly, those of ordinary skill in the art shouldunderstand that, using different components, matters, ingredients, thepresent invention can be implemented with different specific shapes,structures, arrangements, and ratios without departing from the scopeand spirit of the invention. Also, those of skilled in the art willunderstand that the present invention can be used after various changesand modification is made suitable for specific circumstances andoperation conditions within the scope and sprit of the invention.Furthermore, the characteristics explained in the present invention canbe used independently, or each characteristic of the present inventioncan be combined to another characteristic for the use. For example, thecharacteristics described in an exemplary embodiment may beinter-replaced to/from the characteristics described in anotherexemplary embodiment. Accordingly, the embodiments described herein areregarded as merely exemplary and are not meant to limit the presentinvention, and the scope of the present invention is defined by theappended claims.

The present invention has been described in detail. However, it shouldbe understood that the detailed description and specific examples, whileindicating preferred embodiments of the invention, are given by way ofillustration only, since various changes and modifications within thespirit and scope of the invention will become apparent to those skilledin the art from this detailed description.

What is claimed is:
 1. A cable-type secondary battery, comprising: anelectrode assembly including first and second polarity electrodes with athin and long shape, each electrode having a current collector whosecross-section perpendicular to its longitudinal direction is a circular,asymmetrical oval or polygonal shape, and an electrode active materialapplied onto the surface of the current collector, and a separator or anelectrolyte layer interposed between the first and second polarityelectrodes; and a cover member surrounding the electrode assembly,wherein the cable-type secondary battery is provided with a firstpolarity terminal and a second polarity terminal connected to the firstpolarity electrode and the second polarity electrode, respectively, atone end of the cable-type secondary battery; and a housing capconfigured to fix the first and second polarity terminals and cover oneend of the cable-type secondary battery at which the first and secondpolarity terminals are provided, wherein the housing cap includes acoupling unit at the outside thereof, and wherein the coupling unitincludes a spiral groove or a spiral protrusion for screw-coupling. 2.The cable-type secondary battery according to claim 1, wherein thecoupling unit includes a groove or a protrusion for insertion-coupling.3. The cable-type secondary battery according to claim 1, wherein thesecond polarity terminal is integrated with the housing cap.
 4. Thecable-type secondary battery according to claim 1, wherein the firstpolarity electrode is a cathode and the second polarity electrode is ananode; or the first polarity electrode is an anode and the secondpolarity electrode is a cathode.
 5. A device, comprising a powermounting unit capable of mounting the cable-type secondary batterydefined in claim 1 as a power source, wherein the power mounting unitincludes a protruded-type coupling unit or an indented-type couplingunit configured to correspond to the coupling unit of the cable-typesecondary battery.